Pressure-operated valve means for free piston engines



NW0 9 1957 R. W. RousH; JR 2,

PRESSURE-OPERATED VALVE MEANS FOR FREE PISTON ENGINES Filed April 18, 1955 2 Sheets-Sheet l iii? INVENTOR NW 5, R957 R. w. ROUSH, JR 2,811,958

PRESSURE-OPERATED VALVE MEANS FOR FREE PISTON ENGINES Filed April 18, 1955 2 Sheets-Sheet 2 Egg g INVENTOR United States Patent PRESSURE-OPERATED VALVE MEANS FOR FREE PISTON ENGINES Application April 18, 1955, Serial No. 501,887

4 Claims. (Cl. 123-46) This invention relates generally to pressure-operated valve means and more particularly to fuel valve control means for internal combustion engines.

An important object of the present invention is to provide means which Wil enable an internal combustion engine to burn gas or gas mixed with a pilot charge of diesel fuel.

A more specific object of the invention is to provide in a free piston engine valve means between the combustion chamber and a fuel source operable in response to predetermined pressure in the equalizing conduit between the bounce cylinders of the chamber to connect the inlet to the combustion chamber with the fuel source.

A further object of this invention is to provide novel linkages for actuating the fuel control valve in response to various engine pressures.

A still further object of the invention is to provide means for varying the pressure at which the control valve will be opened in response to pressures in the free piston engine.

For a fuller understanding of the above and other objects of this invention reference may behad to the accompanying detailed description and drawings, in which:

Fig. 1 is a schematic view in section of a free piston engine with the novel valve means applied thereto.

Fig. 2 is a detail view in section of the fuel valve means indicating how it is responsive to the pressure in the equalizing conduit between the bounce cylinders of the engine.

Fig. 3 is a madification of the valve actuating and adjusting means.

Fig. 4 is a further modification of the valve actuating and adjusting means.

Fig. 5 is a diagram indicating that the fuel valve is opened in response to the pressure in the equalizing line equally before and after the piston is at top dead center.

Referring first to Fig. 1, the free piston engine indicated generally by the numeral 2 comprises a casing 4. Formed in the casing 4 by suitable wall structure 6 is a combustion chamber 8 and a pair of oppositely disposed chambers 10. Housed in the casing 4 are oppositely disposed piston assemblies 12 having piston faces 14 located in the combustion chamber 8. The piston assemblies 12 are also provided with faces 16 and 18 located in the chamber 1% which divide each of these chambers into a bounce cylinder 2t) and a scavenging air compressor chamber 22. Suitable inlet valves 24 are provided leading into the chambers 10.

Leading from the scavenging air compressor chambers 22 into the scavenging air box 26 are suitable one-Way valves 28. Surrounding the combustion chamber at one end thereof is an inlet manifold 38 leading from the air box 26 into the combustion chamber 8. An exhaust manifold 32 is located around the opposite end of the combustion chamber and includes a plurality of exit ports coverable and uncoverable by the end of the piston assembly 12 adjacent the piston face 14. The manifold 32 is connected to a suitable exhaust pipe 34. Connecting the bounce cylinders 28 to equalize the pressures therein is Patented Nov. 5, 1957 ice an equalizing conduit 36. Communicating with the interior of the combustion chamber is a fuel inlet 38 leading from the combustion chamber to the fuel valve means indicated generally by a numeral 40. Also leading to the fuel valve means 40 is a conduit or pipe 42 which is connected to some suitable conventional pressurized source of fluid fuel. Connecting the valve means 40 to the equalizing conduit 36 is a conduit or pipe 44.

Referring now to Fig. 2, details of one form of the novel control valve means are shown. This valve assembly 40 includes a valve housing or casing 46 which is divided into essentially two chambers 48 and 50 by means of a valve seat restriction 52 including the valve seat 54. Adapted to be seated on seat 54 is a valve 56 which is located adjacent the restriction so that it is adapted, when the valve is open, to move into the chamber 48. The valve 56 is secured to a valve stem 58 which extends through the valve on opposite sides thereof and into the chamber 59. Secured to the stem 58 and reciprocable in the chamber 5% is a piston 68. A face 62 of piston 60 is acted on by pressure from the equalizing conduit 36 through the conduit 44 which is in communication with the end of the chamber 58. Connected to the chamber 50 by means of the conduit 42 is the pressurized source of fuel. The chamber 48, it will be observed, communicates with the inlet 38 to the combustion chamber 8. Threaded on the opposite end of the valve casing 46 is a valve housing extension 64 which includes a wall 66 enclosing the end of chamber 48. The stem 58 extends through wall 66 into a chamber 68 in the extension 64 and is provided on the end thereof with a helical coil spring seat 70. The chamber 68 is closed by a suitable cap 72 threaded on the end of the extension 64 and has suitably extending therethrough a threaded shank 74 on one end of which is mounted a second suitable spring seat 76 located in the chamber 68. Seated on the spring seats 79 and 76 are the ends of a helical coil spring 76. The initial compression of this spring to seat the valve 56 on seat 54 may be regulated by the turning of a handle 88 secured to the opposite end of the threaded shank 74.

The operation of this engine including the novel valve control means is as follows: Assuming the engine to be turning over, as the piston assemblies 12 move outwardly away from each other the pressure in the scavenging air compressor chambers 22 is reduced and valves 24 are caused to open allowing air to enter these chambers. After the piston assemblies 12 reach top dead center and start their return stroke the valves 24 are closed and the valves 28 will be opened thereby compressing the air in chambers 22 and also in the air box 26. This compressed air enters the combustion chamber through the ports of the inlet manifold 3-3 when the end of one of the piston assemblies 12 uncovers the ports in the inlet manifold. At the sametime the air enters the inlet manifold 30 the burnt gases are exhausted through the ports in the exhaust vent hole 32. As the pistons move outwardly toward top dead center, however, they increase the pressures in the bounce cylinders 20 and in the equalizing conduit 36. This increase in pressure acts through the conduit 44 on the face 62 of the piston 68. When the pressure in the equalizing conduit 36 reaches a predetermined amount (see Fig. 5) the piston 60 will move to the left as viewed in Fig. 2 against the action of the spring '78 unseating the valve 56. Unseating the valve 56 connects the chambers 48 and 5t and allows fuel from the pressurized source to flow through these chambers and inlet 38 into the combustion chamber 8. The valve 56 will remain unseated through top dead center of the piston assemblies 12 and for a portion of the return stroke until the pressure in the equalizing conduit 36 and against the face 62 of the piston 6t) again drops to the predetermined amount at which the valve 56 was initially unseated. In this way the 3 V combustion chamber is provided with a charge of fuel and air which is compressed and ignited on the return strokes of the piston assemblies 12.

While any suitable type of fuel may be used and supplied in measured amounts to the combustion chamber 8 by the unique valve assembly just described the device is particularly adaptable for gaseous types of fuel or gas mixed with a pilot charge of diesel fuel.

As already mentioned, if it is desired to change the point in the stroke at which the valve 56 will be opened in response to the pressure in the bounce cylinders 20 it is merely necessary to turn the handle 80 so as to change the position of the spring seat 76 relative to the spring seat 70 when the valve 56 is closed.

From the foregoing description it will be readily apparent that the opening and closing of the valve means 40 is responsive to and proportional to the pressures in the bounce cylinders 20, the pressures in the scavenging air compressor chambers 22 or in the combustion chamber itself. While the valve has been shown as opening pre determined amounts before and after top dead center of the piston, suitable time-delay means may be employed in combination with the valve means to cause the valve assembly to open and connect the fuel source with the combustion chamber for any preferred length of time during any particular period of the cycle in order to achieve the optimum of operation.

Referring now to Fig. 3, a modification of the valve assembly is shown. In this instance a piston and cylinder assembly comprising a cylinder 82 and a piston 84 is connected by means of conduit 44 to the pressure equalizing conduit 36 so that the pressure in the conduit 36 acts against the face 86 of the piston. Connected to the piston 84 is a rod 88 which engages by means of a suitable ball and socket joint one end of a rocker arm 90 fulcrumed intermediate the ends thereof on the support 92. The opposite end 94 of rocker 90 abuts a spring seat 96 located in one end of a suitable spring housing 98. The opposite end of housing 98 is provided with a cap 100 which has threaded therethrough a shank 102 provided with a handle 104 on one end thereof. On the opposite end of shank 102 is a spring seat 106 located within the housing 98 and spaced from spring 96. Interposed between the seats 96 and 106 is a helical coil spring 108. The spring seat 96 is suitably connected to the stem 110 of a valve 112 seated on a seat 114 located in a valve housing 116. The valve housing 116 is divided into two chambers 118 and 120 by seated valve 112, the first of which communicates with the combustion chamber through the inlet 38 and the second of which is connected by means of the conduit 4-2 to the fuel pressure source.

The operation of this valve means then is as follows: At a predetermined point in the outgoing stroke of the piston assemblies 12 the pressure in the cylinder 82 against the face of the piston 86 rises to an amount sufficient to cause the piston to move to the right as viewed in Fig. 3 against one end of the rocker arm which is biased in a counterclockwise direction by spring 108 acting on the opposite end of the rocker 90. In other Words, the rocker arm 90 is caused to turn in a clockwise direction moving its end 94 againstthe seat 96 so that the valve stem 110 and valve 112 are moved to the left as viewed in the figure and valve 112 is unseated thereby connecting the fuel pressure source to the inlet 38 through the chambers 120 and 118. The valve means shown in Fig. 3 is also capable of adjustment so as to change its responsiveness to the pressure in the equalizing conduit 36 and bounce cylinders 20. This is accomplished by turning of the handle 104 which changes the biasing effect of spring 108 on seat 96, the end 94 of rocker 90 and, of course, the valve 112.

A further modification of the valve means indicated generally by the numeral 40 in Fig. 1 is shown in Fig. 4. Since certain portions of this assembly are the same as those shown in Fig. 3, the same reference characters will be used in those instances. It will be noted in Fig. 4 that the rocker whose one end is engaged by the rod 88 has its opposite end 94 engaging the end of the valve stem and that the valve 112 is normally maintained seated by means of a spring 122 interposed between a spring seat 124 fixed to stem 110 and a seat 126 slidable on stem 110. In the modification shown in Fig. 4, however, the biasing effect of spring 122 to maintain valve 112 seated is varied by means of a second rocker arm 128 pivotally mounted on the housing 116 and fulcrumed at 130. The rocker arm 128 has one end engageable with the movable spring seat 126 and the opposite end in engagement with a shank 132 threaded in a fixed support 134 and turnable by a handle 136. In this case, to effect adjustment of the bias of the spring 122 on valve 112 the handle 136 is turned so as to cause rocker arm 128 to move about its fulcrum point 130. This will cause seat 126 to move toward or away from seat 124 as desired thus changing the biasing effect of spring 122 which tends to seat valve 112.

What I claim is:

1. In a free piston engine including a central combustion chamber and oppositely disposed piston cushioning cylinders in which oppositely reciprocable piston assemblies are housed, a pressure equalizing conduit extending between said piston cushioning cylinders, a source of fuel under pressure, a fuel inlet to said combustion chamber, and valve means between said inlet and source responsive to predetermined pressures in said equalizing conduit to connect said inlet to said source.

2. In a free piston engine including a central combustion chamber and oppositely disposed piston cushioning cylinders in which oppositely reciprocable piston assemblies are housed, a pressure equalizing conduit extending between said piston cushioning cylinders, a source of fuel under pressure, a fuel inlet to said combustion chamber, valve means between said inlet and source responsive to predetermined pressures in said equalizing conduit to connect said inlet to said source, and means connected to said valve means adjustable to vary the predetermined pressure at which said inlet is connected to said source.

3. In a free piston engine including a central combustion chamber and oppositely disposed piston cushioning cylinders in which oppositely reciprocable piston assemblies are housed, a pressure equalizing conduit extending between said piston cushioning cylinders, a source of fuel under pressure, a fuel inlet to said combustion chamber, a valve housing, a valve in said valve housing when seated dividing said housing into first and second chambers, said first chamber being connected to said inlet, said second chamber being connected to said source, a piston in said second chamber and connected to said valve, a conduit connecting said equalizing conduit with a face of said piston thereby biasing said valve according to the pressure in said equalizing conduit, and a spring operatively connected to said valve and biasing said valve in opposition to the bias of the pressure in said equalizing conduit.

4. In a free piston engine including a central combustion chamber and oppositely disposed piston cushioning cylinders in which oppositely reciprocable piston assemblies are housed, a pressure equalizing conduit extending between said piston cushioning cylinders, a source of fuel under pressure, a fuel inlet to said combustion chamber, a valve housing, a valve in said valve housing When seated dividing said housing into first and second chambers, said first chamber being connected to said inlet, said second chamber being connected to said source, a piston in said second chamber and connected to said valve, a conduit connecting said equalizing conduit with a face of said piston thereby biasing said valve according to the pressure in said equalizing conduit, a spring operatively connected to said valve and biasing said valve in opposition to the bias of the pressure in said equalizing conduit, and means for regulating the bias of said spring on said valve.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Neff Mar. 11, 1919 Spohrer Dec. 7, 1920 5 Pescara June 20, 1939 Steiner June 24, 1941 Barton Nov. 10, 1942 6 FOREIGN PATENTS Great Britain Nov. 24, 1937 OTHER REFERENCES sr. No. 348,726, Hurst (A. P. 0. published May 11,1943. 

